http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51628
--- Comment #18 from incrediball <peter at axium dot co.nz> 2013-04-02 20:21:06 UTC --- Not sure if I can agree with (or understand) this comment. If we use my example of the address of an int in a packed structure being assigned to an int* then one could argue that there is a kind of implicit cast happening. The pointer is to an integer WITH the default alignment which would be 4 on the ARM system I work with. The int in the struct has an alignment of 1 and so the two types need to be regarded as being incompatible and there should be an unconditional warning or at least -Wcast-align should enable such a warning. I don't know what BLKmode is but if you're speaking of making an int* type generally able to access the int regardless of its alignment, I think this is the wrong way to go because code size will explode and efficiency will go out the window. However if the int* would be declared with some special attribute then, sure, generate whatever code that is necessary to access the int and the above mentioned warning can be suppressed in this case (wouldn't the code generated be much the same code that is used to directly access the int in the packed struct anyway?) However this would be the second (optional) step, the first thing is that the compiler needs to emit a warning explaining that the code that it is generating is broken.
